The Porridge reboot is currently showing on BBC One (Picture: BBC Studios)

As far as classic comedy is concerned, the original series of prison sitcom Porridge has proved to be a perennial goldmine for the BBC.

Since it was first shown on BBC One between 1974 and 1977, the series has been re-shown, exported, made into a film, sold on video, then on DVD and is now available to be streamed to a device of the viewer’s choice.

Driven by the comic genius of the late Ronnie Barker as cynical old lag Norman Stanley Fletcher, watching Porridge is probably as close to the prison experience as most viewers will ever get.

A 21st century reboot would seem to be a very low risk gamble. So what’s not to like?

In the 2017 revival, young Nigel Fletcher – the original Fletch’s grandson (played by Kevin Bishop) – is doing a 5-year stretch for the modern offence of cyber-crime.

Although the set representing the prison environment may have been updated, the basic premise remains the same: a cheeky, loveable rogue interacting with fellow cons and prison staff alike, while trying to get one over on anyone who crosses his path.

It’s gentle humour, played for laughs.

To anyone who has served time inside, it’s obvious that the designers have done their homework reasonably well.

The prison wing looks fairly realistic (although buzzing electronic cell locks are more a feature of US jails than British prisons).

The inmates’ uniforms of t-shirts and jogging bottoms aren’t too far from what is actually worn by many male prisoners (female prisoners don’t have to wear jail clothing at all these days) and although there are occasional bloopers, such as Fletch spraying it on with an aerosol can – which are strictly forbidden in jails as potential offensive weapons – it doesn’t detract too much from the show.

The role played by young Fletcher in the first episode is also not so very far from the truth.

Intelligent, literate inmates do write letters on behalf of the 50% of adult prisoners who are functionally illiterate.

Samaritan-trained Listeners support fellow prisoners who are suicidal or self-harming, while Insiders dispense advice to other inmates who have nowhere else to turn.

(Picture: BBC Studios)

Some rogues – like the wily Fletch – do charge for these services, but the vast majority don’t.

What will be much more worrying to anyone who is concerned about prison reform is the danger that a new generation of viewers may come to regard the fictional ‘HMP Wakeley’ as an accurate representation of daily life on a prison wing.

It isn’t and it’s difficult to see how a comedy could be made from anything approaching the current reality inside our dangerous, overcrowded and understaffed jails.

Well, thus far, we’ve seen no violence, which is a daily occurrence across our troubled prison system.

There have been no suicides despite the current rates of self-inflicted deaths running at around one every three days.

And the most heinous example of contraband smuggling we’ve seen is a small box of chocolates Fletcher is handed by an officer he’s been advising on his love life.

(Picture: BBC Studios)

No mention of the appalling drug epidemic that has been sweeping our jails in recent years or the rising number of corrupt prison staff being jailed for supplying drugs has been made.

No evidence, either, of the soaring levels of serious mental illness in our jails because prisons are increasingly being used to warehouse those who have been failed in the community due to massive cuts to local mental health budgets.

I seriously doubt that the BBC, or any other responsible broadcaster, would consider setting a new comedy show inside a psychiatric hospital, yet prisons are still seen as fair game for the comic writer’s pen.

Of course, it would be difficult to get much comedy value out of our real prisons: hellholes of violence, drug addiction, bullying, self-mutilation and suicidal despair where even the frontline staff are fearful of not coming home at the end of a shift.

How would young Fletch cope with any of that on a daily basis?

I suppose if the Porridge 2017 reboot reflected reality, the growing pile of corpses just wouldn’t get many laughs.